This invention relates to a solid-state color imaging apparatus.
An interline transfer CCD imaging element (hereinafter, abbreviated to "IL-CCD imaging element") comprises a plurality of picture elements arrayed regularly in both a horizontal direction and a vertical direction to form horizontal rows and vertical columns. Vertical CCD registers transfer, in the vertical direction, signal charges which are photoelectrically converted by and stored in the picture elements. At the ends of the vertical column, a horizontal CCD register transfers them in the horizontal direction to an output portion.
The IL-CCD imaging element is capable of two sorts of read-out operations which are a frame storage operation in which the signal charges stored in the picture elements are read out during every frame period, and a field storage operation in which they are read out during every field period. The time of the field storage operation is half that of the frame storage time and results in less afterimage. For this reason, the development of a single-plate color imaging device for effecting the field storage operation is being promoted.
In color imaging by the use of the IL-CCD imaging element, the color separated images of a subject are formed by color filters. The color separated images are picked up by the IL-CCD imaging element. The output signals of the IL-CCD imaging element are processed, thereby to obtain chrominance and luminance signals.
A conventional IL-CCD imaging apparatus having a conventional color filter has a disadvantage, to be described below. The signal of each horizontal line is a sum of the signal charges obtained by independently and spatially sampling the two adjacent picture elements in the vertical direction and is not constituted by a single horizontal line signal. This causes a very large vertical color error in the output signal of the conventional imaging apparatus when the apparatus picks up a subject having a vertical repetition frequency wherein white and black picture elements alternately exist in the vertical direction. That is, a sharp vertical contour portion having no vertical correlation between two adjacent horizontal picture element rows inevitably generates a vertical color error under achromatic light.